And no, it’s not that she’s a lesbian – despite what more than a few women dreamed about after seeing the actress play Sapphic in 1995’s “Showgirls,” 1996’s “Bound” and the Sundance favorite “Prey for Rock and Roll,” which opens this Friday.

The TriBeCa-based indie star admits she gets hit on by “lots of women” and that her “guy friends are really jealous” – but she is, in fact, solidly heterosexual and has been linked to such hotties as Lenny Kravitz and Owen Wilson.

Gershon’s actual secret is much more scandalous.

“My big secret is that I used to want to be a country singer,” Gershon tells The Post of her childhood in Los Angeles.

“When I was a kid, I’d sit in my bedroom with my guitar and sing Bonnie Raitt and Patsy Cline tunes.”

After moving to New York in the 1980s and studying theater with David Mamet, Gershon put her music plans on hold.

But at the age of 40, she is finally making her music dreams come true, thanks to “Prey for Rock and Roll,” in which she plays a tough punk rocker in an all-girl band that also features Drea de Matteo of “The Sopranos.”

Gershon performs her own songs in the movie, and she really rocks. She’s so good, in fact, that she’s spending this month on tour with a band called Clamdandy.

Gershon sings, plays guitar and even does a few tunes on the jew’s-harp, which she has played since she was a kid.

Even though Gershon has only been rocking live for a few weeks, jitters aren’t really a problem.

“I grew up around musicians,” she says. “So even though I haven’t really been in a band before, I feel comfortable with it.”

Gershon’s older sister, Tracy, is a country-music executive in Nashville, married to Steve Fischl, who played pedal-steel guitar in Emmylou Harris’ band and produced the Dixie Chicks’ first two albums.

And her uncle, Jack Elliott, wrote such classic TV theme songs as “Barney Miller,” “The Love Boat,” and “Charlie’s Angels.” In the mid-’60s, he adopted Benny Medina, who grew up to be Jennifer Lopez’s longtime manager and the creator of Will Smith’s “The Fresh Prince of Bel Air.”

Gershon has always been friends with rock stars, including Bob Dylan, whom she once punched in the nose.

In the mid-’90s, Gershon and Dylan had the same trainer, and every Thursday, he would put them in boxing gloves for a few sparring rounds in an L.A. gym.

One day, Dylan popped Gershon in the face and she saw red – socking the rock legend and sending him to the canvas.

“I was like, ‘Oh my God, I broke Bob Dylan’s jaw,’ ” Gershon recalls.

Happily, the damage wasn’t that serious, and when Dylan got off the mat, he told her, “I need a good woman to kick my ass every now and then.”